Negroes and for the community to which he is migrating if the tempo of growth were dampened" (51). This differential in fertility rates between Negroes and whites (the average number of children born to white women was 2.5 and to Negro women 2.8 in 1960) has been a factor strengthening popular sentiment among whites for providing birth control assistance to poor, especially Negro, women.* So far we have noted several instances of lower social classes and minority groups having high fertility rates in relation to other social groups. Ireland provides an example of a political problem which was partially relieved by a lower population growth rate within a minority group. From the end of the 18th century through the first third of the 19th century, Ireland had about one third of the population of the United Kingdom. By the 1880's, however, the proportion had dropped to only one seventh. The decline in the Irish population, a decline incidentally not simply in proportion to the English but also in absolute numbers, was due partly to the decline in fertility and partly to the vast outpouring of migrants to the United States. This decline in population made a vast difference in how the United Kingdom was willing to cope with the Irish problem. One need only imagine how the British would have responded to the demand for independence if Ireland had been larger. The British would presumably have been even more fearful of an alliance between the Irish and the French and later between the Germans and the Irish. It should also be noted that from the middle of the 19th century to the middle of the 20th century Ireland's population had decreased by half, but the decline was greater for the Catholic areas of Ireland than for Protestant Ulster. Changing fertility rates in Northern Ireland have, however, created a new set of problems for the British. The rise of a Catholic civil rights movement in Northern Ireland in the past few years, pressing for the abolition of property restrictions on the right to vote so as to permit greater Catholic representation in legislative bodies comes at a time when the proportion of adult Catholics has markedly increased as a consequence of higher fertility rates among Catholics. These examples point to a shift from concern with differential fertility rates among socioeconomic classes (an issue in much of western Europe in the 19th century when conflicts were mainly along class lines) to a concern with differential fertility rates among populations having different cultural values. Few writers will speak today as Myrdal did as late as 1938 of "the great and obnoxious fertility differences between the overfertile poor strata and the underfertile middle and upper strata" (3), although many will speak readily of the changing proportions of racial, religious, or tribal groups. *Sec J. Mayone Stycos, "Opinion, Ideology, and Population Problems-Some Sources of Domestic and Foreign Opposition to Birth Control," in this volume. consequences.ion, for example, as a result of the dense concentration of automobiles. The cconomies-of-scale argument, therefore, cuts both ways. less important.